Need Help with SRDF Groups(RA Groups)

Question

Hi I need help with...SRDF RA Groups

I have 8 RA Directors on V-max and have created a RA group with 2 directors from local and 2 directors from Remote.

Now as i do not have many SRDF devices/groups or replications configured i can pick up any.

But one the Sym gets full of devices and they need to be replicated how do i choose from existing RA groups ...

How to decide which one shall be used for balanced RA workload and When shall be the decision taken to create a new SRDF RA group..

As i dont want to overload one RA group with lot of workload..i know sym has a max of 256 RA groups for 5874 i.e 32 group per port and 6 is the max. number for good performance ...but i want to how does the decision making shall be guided/or taken for creation of RA group..

All the help is appreciated and any particular example from thier current working environment is welcomed.

Thanks

Tanwar2 · Answer

First of all what network protcols you have put in to connect two Symm.

Is it FC or GigE based ?.

and base on the protocls then again there are lot of parameters which plays important role while deploying SRDF.

What is the badnwitdh,Flow control mechanism,BB credits etc..

then how much data you need to replicate,No. of servers.

What is the RPO/RTO have decided by the organization.

No. of servers you need to configure according to which SRDF mode.

then you need to segregate your RA group as well ,which one you want to use for which mode etc etc.

Sanjeev Tanwar

bodnarg · Answer

Keep it as simple as possible since you have the ability to move devices between groups as needed for testing.

My suggestion is to only split into multiple groups based on the following:

* Requirement to run different modes (Adapter Copy, Async, Sync, etc.) - this is a requirement anyhow

* Different target units (once again a requirement)

* Desire to group things by application or business unit for easier testing/failover. Don't get too carried away - if you need to test a few volumes from a group every once in a while you can use the movepair function to move those to a temporary group.

* Need to be able to throttle a single group with QoS settings to limit its impact on other.

The less groups you have to manage the better off you will be in the long term - it is unlikely you will have enough devices in a single frame to require you to have multiple RDF groups for a technical reason.

Irshad11_725313 · Answer

We dont have any mode requirement we need balanced I/O Traffic across all RA's not Overloading any..

Irshad11_725313 · Answer

Is it FC or GigE based ?. Its GigE What is the badnwitdh,Flow control mechanism,BB credits etc..? how to look for this info...i know its 4 Gig backend connectivity..soon to be upgraded to 8 then  how much data you need to replicate,No. of servers.? Its about 120 Servers

JasonBailey · Answer

to make this decision you need to look at the performance stats of the RFs in the RA groups

you can use ControlCenter Performance Manager or Symmetrix Performance Manager to do this

otherwise if you don't have these then you can use symstat as last resort

Symmetrix

Need Help with SRDF Groups(RA Groups)

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